Looking at make_room and alloc_up, we claim the first chunk (1 MB)but we never claim any more. mem_end is always set to alloc_topwhich is the top of our available address space, guaranteeing we willnever call alloc_up and claim more memory.

Also alloc_up wasn't setting alloc_bottom to the bottom of theavailable address space.

This doesn't help the box to boot, but we at least fail withan obvious error. We could relocate the device tree in a futurepatch.